ruby - Creating a object with nested form rails -

i have 3 tables: members, meetings, meeting_has_members. models are:

member.rb

class member < activerecord::base   has_many :meeting_has_members  has_many :meetings, through: :meeting_has_members   accepts_nested_attributes_for :meeting_has_members  accepts_nested_attributes_for :meetings 

meeting.rb

class meeting < activerecord::base   has_many :meeting_has_members  has_many :members, through: :meeting_has_members   accepts_nested_attributes_for :meeting_has_members  accepts_nested_attributes_for :members 

meeting_has_member.rb

class meetinghasmember < activerecord::base   belongs_to :member  belongs_to :meeting 

what i'm trying is, while creating meeting, able add members it, , when submitted, create relation meeting_has_member. table meeting_has_members have 2 columns: member_id, meeting_id.

thats meeting_controller:

meeting_controller.rb

 class meetingscontroller < applicationcontroller    before_action :set_meeting, only: [:show, :edit, :update, :destroy]    def index     @meetings = meeting.all   end    def show   end    def new     @meeting = meeting.new     @meeting_has_members = @meeting.meeting_has_members.build   end    def edit   end    def create     @meeting = meeting.new(meeting_params)      respond_to |format|       if @meeting.save         format.html { redirect_to @meeting, notice: 'meeting created.' }         format.json { render :show, status: :created, location: @meeting }       else         format.html { render :new }         format.json { render json: @meeting.errors, status: :unprocessable_entity }       end     end   end    def update     respond_to |format|       if @meeting.update(meeting_params)         format.html { redirect_to @meeting, notice: 'meeting updated.' }         format.json { render :show, status: :ok, location: @meeting }       else         format.html { render :edit }         format.json { render json: @meeting.errors, status: :unprocessable_entity }       end     end   end    def destroy     @meeting.destroy     respond_to |format|       format.html { redirect_to meetings_url, notice: 'meeting destroyed.' }       format.json { head :no_content }     end   end    private    def set_meeting     @meeting = meeting.find(params[:id])   end    def meeting_params     params.require(:meeting).permit(:meeting_name, :meeting_description, :meeting_date, :agenda_id,                                   meeting_has_members_attributes: [:id],                                   members_attributes: [:id])   end  end 

and form create meeting is:

meetings/_form.html.erb

<%= form_for(@meeting) |f| %>   <% if @meeting.errors.any? %>     <div id="error_explanation">       <h2><%= pluralize(@meeting.errors.count, "error") %> prohibited meeting being saved:</h2>        <ul>        <% @meeting.errors.full_messages.each |message| %>         <li><%= message %></li>        <% end %>       </ul>     </div> <% end %>    <div class="field">     <%= f.label :meeting_name %><br>     <%= f.text_field :meeting_name %>   </div>   <div class="field">     <%= f.label :meeting_description %><br>     <%= f.text_field :meeting_description %>   </div>   <div class="field">     <%= f.label :meeting_date %><br>     <%= f.date_select :meeting_date %>   </div>   <div class="field">     <%= f.label :agenda_id %>     <%= f.select :agenda_id, agenda.all.collect { |p| [p.agenda_name, p.id] } %>   </div>     <%= f.fields_for :meeting_has_members |builder| %>      <%= builder.label :member_id %>      <%= builder.select :member_id, member.all.collect { |m| [m.member_name, m.id] }%>     <% end %>   <div class="actions">   <%= f.submit %>   </div> <% end %> 

when submit, creates, on meeting_has_members table meeting_id, doesn't set value member_id, should select in nested form.

can me this?

your meeting_params should

def meeting_params     params.require(:meeting).permit(:meeting_name, :meeting_description, :meeting_date, :agenda_id, meeting_has_members_attributes: [:id, :member_id]) end 

notice added :member_id in meeting_has_members_attributes , removed members_attributes not saving them.